The invention relates to a mounting system for metallic support shells at implantable joints with pin-like anchoring elements which can be anchored in the bone while passing through the support shell and which themselves have a head which lies on a shoulder of the implant in the axial direction of the pin-like anchoring element.
Support shells are used in artificial joints if the material of a bearing surface of the joint is in itself not sufficiently stiff in order to achieve a lasting anchorage in the bone, or if the bearing surface is to be made replaceable, or if the bearing material is not particularly well tolerated by the body. Typical support shells are tibia platforms and outer shells of artificial hip or shoulder joints. With respect to the primary anchoring of these support shells the surgeon is bound by the state of the bone at the intended mounting location and should therefore have a modular system available which permits different mounting means without alterations of the support shell.
Thus EP-B-0 499 475 shows a hip joint socket, the outer shell of which has a plurality of radial bores into which pins can be inserted and anchored. Other authors provide bone screws in order to produce a contact pressure force at the support shell in the direction of the screw axis. These systems have one disadvantage: They do not seal and therefore cannot prevent abraded matter passing through the bores and arriving at the parts of the bone lying behind them.